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bug#13098: [PATCH] cut.c: Fix memory leak
From: |
Jim Meyering |
Subject: |
bug#13098: [PATCH] cut.c: Fix memory leak |
Date: |
Sat, 08 Dec 2012 21:27:12 +0100 |
Jim Meyering wrote:
> Jim Meyering wrote:
>
>> Pádraig Brady wrote:
>> ...
>>> How about the attached?
>>
>>> From: Cojocaru Alexandru <address@hidden>
>>> Date: Thu, 6 Dec 2012 03:03:41 +0100
>>> Subject: [PATCH] cut: avoid a redundant heap allocation
>>>
>>> * src/cut.c (set_fields): Don't allocate memory for
>>> `printable_field' if there are no finite ranges.
>>> The extra allocation was introduced via commit v8.10-3-g2e636af.
>> ...
>>
>> Thanks to both of you.
>> That's a fine bug fix, actually.
>> Consider that before, this would fail on my 64-bit system:
>>
>> $ : | cut -b999999999999999999-
>> cut: memory exhausted
>> [Exit 1]
>> $
>>
>> Now, it no longer tries to allocate all that memory, so completes normally:
>>
>> $ : | cut -b999999999999999999-
>> $
>
> Note that on a 32-bit system it fails the same way in both cases:
>
> $ : | src/cut -b999999999999999999-
> src/cut: byte offset '999999999999999999' is too large
> [Exit 1]
>
> And even with 2^32-1, it'll probably just allocate the memory,
> assuming 500MB doesn't cause trouble.
> To differentiate portably, we probably have to use ulimit:
>
> Limit VM to 22000k, but make the old cut require about 10x that:
>
> $ (ulimit -v 22000; :| cut -b$(echo 2^31|bc)-)
> cut: memory exhausted
> [Exit 1]
>
> The new, just-built one passes:
>
> $ (ulimit -v 22000; :| ./cut -b$(echo 2^31|bc)-)
> $
>
> If someone feels like turning the above into a test
> case, please do (and update NEWS). Otherwise, I'll
> get to it over the weekend.
Here it is:
>From a2833b8399f56bff6fe08eb212c01a5cb1b74606 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Sat, 8 Dec 2012 12:04:14 -0800
Subject: [PATCH] tests: add test case and note that last week's cut change is
a bug fix
* tests/misc/cut-huge-to-eol-range.sh: New test, showing that
the change in v8.20-51-g7d03466 is a bug fix after all.
* tests/local.mk (all_tests): Add it.
* NEWS (Bug fixes): Mention it.
---
NEWS | 4 ++++
tests/local.mk | 1 +
tests/misc/cut-huge-to-eol-range.sh | 30 ++++++++++++++++++++++++++++++
3 files changed, 35 insertions(+)
create mode 100755 tests/misc/cut-huge-to-eol-range.sh
diff --git a/NEWS b/NEWS
index 7c17869..a7a5bc3 100644
--- a/NEWS
+++ b/NEWS
@@ -10,6 +10,10 @@ GNU coreutils NEWS -*-
outline -*-
** Bug fixes
+ cut with a range like "N-" no longer allocates N/8 bytes. That buffer
+ would never be used, and allocation failure could cause cut to fail.
+ [bug introduced in coreutils-8.10]
+
cut no longer accepts the invalid range 0-, which made it print empty lines.
Instead, cut now fails and emits an appropriate diagnostic.
[This bug was present in "the beginning".]
diff --git a/tests/local.mk b/tests/local.mk
index d5bb6f7..5eeddd5 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -246,6 +246,7 @@ all_tests = \
tests/misc/pwd-option.sh \
tests/misc/chcon-fail.sh \
tests/misc/cut.pl \
+ tests/misc/cut-huge-to-eol-range.sh \
tests/misc/wc.pl \
tests/misc/wc-files0-from.pl \
tests/misc/wc-files0.sh \
diff --git a/tests/misc/cut-huge-to-eol-range.sh
b/tests/misc/cut-huge-to-eol-range.sh
new file mode 100755
index 0000000..fea8505
--- /dev/null
+++ b/tests/misc/cut-huge-to-eol-range.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+# Ensure that cut does not allocate mem for a range like -b9999999999999-
+
+# Copyright (C) 2012 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ cut
+require_ulimit_
+
+# 2^31-1
+# From coreutils-8.10 through 8.20, this would make cut try to allocate
+# a 256MiB bit vector. With a 20MB limit on VM, the following would fail.
+(ulimit -v 20000; : | cut -b2147483647- > err 2>&1) || fail=1
+
+compare /dev/null err || fail=1
+
+Exit $fail
--
1.8.0.1.352.gfb4c622